The Hudson runs past Watervliet in every state water knows — high and brown in April, low and glittering in August, edged with ice by January — and Arsenal City Lawn Sprinklers works both ends of that year. The warm months mean irrigation: lines laid, heads set and adjusted, spring start-ups, and the fall blow-out before the first hard freeze reaches the valley floor. Lawns here are flat river-bottom yards behind flat-fronted houses, and even watering is what keeps them green through an August that bakes the pavement by ten. Then the calendar turns and the same trucks come back with plows, opening drives and lots and salting where the daytime melt refreezes overnight. Two halves of one year, both of them about water going exactly where it should.